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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Stability Index

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MarkV
Deckhand

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6 Posts

Initially Posted - 12/04/2014 : 16:06:50

Steve,

Thanks for sending the 2 webb sights regarding my inquiry. The 1st one doesn't get into stability indexing, and the 2nd I can't access by clicking on it. I'll try googling it and see if I get in.

Best,

Mark

Edited by - on

Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 12/04/2014 : 16:26:51

Mark, the second link doesn't open up a new window. It downloads a pdf file. On my laptop, which is runnin g Windows 8.1, using the Chrome browser, when I click on the link, it creates a small rectangle in the lower left corner of the page. Inside the rectangle, it says "imsbk4ge(4).pdf" If you find that, click on it. It should open the pdf file.

Another way to find it is to go to your "Downloads" folder. You should find a download labelled "imsbk4ge(4).pdf" Click on it.

Edited by - Steve Milby on 12/04/2014 16:32:55

MarkV
Deckhand

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6 Posts

Response Posted - 12/04/2014 : 17:50:59

Steve, I'll try those recommendations, thanks.
I was recently reading a review of the new boat: Koopmans 28SQ in Sailing magazine. It has a capsize stability index of 2, "meaning its stability is on par with offshore boats". I thought it would be interesting to compare this 135K $ boat to a Cat. 25. Not that they are equals.
I practically fell off my stool, I was laughing so hard @ Dave's comment about the swing keel ripping asunder through the belly of my bilge. Thank You Dave!! I'm on a 9 mile long pond and feel like a baby in an incubator, (too safe). I'd absolutely love to do coastal. Maine? Florida? Wow!! I'll tell you one thing , if I was dosing off @ the tiller in open water, when that took place, I'd save BIG TIME , on Star Bucks, because I wouldn't need any stimulents for a week or more!!

I'm pretty sure my Cat. 25 is no Pacific Seacraft, and the guy that sold it to me for 1000.00 $, lock, stock, and barrel, including a trailer and new sails would agree. But, if I get the chance to lay her down on her side, you can bet your bottom dollar I'll bury her toe rail deep.
The worrying is up to the "engineers" ----- boat designers to figure out. If she sinks like a rock, as long as I'm swimming on the surface I'll happily just get another boat.
My little Hurley 20 has been back and forth to England from NY 3 times, (not by me). She carries a Loydes plaque @ the companion way. Everything is relative. But fun, and an adrenaline rush here and there are what makes it all worth while.
I sail to feel alive, and I push my Hobie 16 or anything else I own.
Best ,

Mark

P.S.: This Forum is very informative and interesting. To me when wind, weather, and circumstances come together, SAILING can not be beaten. Keep it up!

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 12/04/2014 : 19:55:13

Here's another good summary of stability factor computations:

http://www.richgard.com/yacht_stability.htm

BTW, the C25 capsize screen is 1.95, which is a simplistic measure indicating (because it's less than 2.0) it will right itself from a knockdown, although not from being rolled. Thus, it is considered safe on the ocean, but not for getting caught in a big ocean storm, which is part of what separates it from the "blue water" category.

Edited by - Stinkpotter on 12/04/2014 20:04:13

capelyddol
1st Mate

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USA
62 Posts

Response Posted - 12/04/2014 : 20:23:47

Geeez! You wouldn't get me crossing the Atlantic in a 20-footer. The Hurley 20 was a slightly larger version of the renowned Hurley Marine 'Silhouette', a beamy 17-footer that bobbed around like a wine cork. My father and I owned one for a number of years until I happily agreed to sell it and buy a 22-foot Debutante, which proved a much more comfortable boat to sail.
I'm not sure I put much store by figures when it comes to sailing. 'Stability factors' and other such computerized statistics are fine for the boffins in the offices, but sailing is about the seat of your pants. A boat has much in common with a woman. Take the time to get to know her and she'll soon tell you how far you can push her before she slaps you across the face and says 'that's far enough'.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 12/04/2014 : 21:08:06

No argument there! And the computed stability factors are all somewhat simplistic, ignoring some factor of the boat's design or construction. The Capsize Screen was developed as a simplistic indicator of which boat should or should not be allowed to participate in ocean races. It is not intended to help buyers choose a boat that will "feel right" or take care of their needs. But some other indices can help a buyer understand the differences between boats without actually sailing them in all kinds of conditions. The Motion Comfort Ratio is higher for the C-25 than for the C-250, and I suspect that would be borne out in a comparison in some rough water to see where you get "slapped in the face."

I've seen "stability curves" for some boats, showing the righting moment at all degrees of heel. Those with high "initial stability" (resistance to heel) tend to have low "ultimate stability" (recovery from knockdown), and vice versa. Hull shape has as much to do with it as ballast or even the length/beam ratio.

Edited by - on

sweetcraft
Admiral

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USA
816 Posts

Response Posted - 12/05/2014 : 01:04:33

Just a note on sability of the 25. During the racing years of the 25TRSK we took 3 knockdowns in different races, two with spinaker and one with a 150. Each time with five crew and the duration was 8 to 9 seconds which is an estimate because its hard to count during the event. The boat continued in the race on course with stories to last forever. The boat does take care of it's self and we have great confidance in it. I don't believe it is a blue water boat with the poptop and the swing keel. It does provide a safe ride if the gear is checked and maintained.
Dave is our good source for information to help keep us safe and informed. Thanks again Dave

Edited by - on

dasreboot
Admiral

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803 Posts

Response Posted - 12/05/2014 : 05:29:38

quote:
Originally posted by sweetcraft

we took 3 knockdowns in different races, two with spinaker and one with a 150.

I've never had one in the c25 more than 50 degrees or so. I've always wondered if you suffer an 80 or 90 degree knockdown, is the companionway above the water?

Edited by - on

Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 12/05/2014 : 06:29:32

quote:
Originally posted by dasreboot

quote:
Originally posted by sweetcraft

we took 3 knockdowns in different races, two with spinaker and one with a 150.

I've never had one in the c25 more than 50 degrees or so. I've always wondered if you suffer an 80 or 90 degree knockdown, is the companionway above the water?

I intentionally sailed my TR/FK C25 overpowered several times, heeling it until the rudder lifted out of the water. At that point, the boat laid on it's side until I eased the mainsheet. On two occasions, when it happened quickly, the lid of the cockpit locker on the (port) high side swung open. The lid on the low side never opened, but it certainly could have. In most instances, no water came over the gunwale on the low side. On a couple of occasions, when it happened fast, a couple gallons of water splashed over the gunwale, but the stern has ample buoyancy so that the stern floats high, and not much water comes in. If a big wave hit the stern while it was lying on it's side, that would be bad, because a breaking wave would roll the gunwale under even further and begin to fill the cockpit and weigh it down. I imagine that could press the stern down enough to cause water to pour into the open cockpit lockers and perhaps into the open companionway. I think it's very unlikely that would happen on a small, inland lake, where you don't usually find big, breaking waves. It could happen on a big lake or Bay, or in open water, where waves can build high over a long fetch.

After I saw that, I had a better understanding of the importance of dogging down the hatches, replacing the hatchboards, and securing the cockpit locker hatches in rough weather. That is the kind of situation that could lead to a roll-over, and the catastrophic damage that Dave talked about. I have never heard of a single instance where that has actually happened, but I think it's safe to say that Frank Butler meant the swing keel C25, especially with a pop top, to be kept out of conditions where a roll over might happen. A 5 foot long, 1500# cast iron keel supported by a single pin in fiberglass isn't meant to go through those gyrations. I think the long history of the C25 swinger attests that it is a fundamentally safe design, as long as it is properly maintained, and as long as you don't sail it into conditions beyond it's design parameters. In sheltered waters, it's usually easy enough to find a place to anchor and wait until storm conditions abate.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 12/05/2014 : 08:14:49

quote:
Originally posted by Steve Milby

...I think the long history of the C25 swinger attests that it is a fundamentally safe design, as long as it is properly maintained, and as long as you don't sail it into conditions beyond it's design parameters. In sheltered waters, it's usually easy enough to find a place to anchor and wait until storm conditions abate.

Yup! We were in a faint breeze halfway between Mystic, CT and Mattituck, Long Island, delivering our new-to-us C-25 home to western CT, when NOAA warned us of a squall line with 70+ gusts moving up the Sound... We cranked up the outboard and furled the sails as we scrambled back to the CT River, about an hour away. The instant we picked up a mooring in a cove there, it hit. We ended up with tree branches in the cockpit, and were very glad not to be in the middle of L.I.S! The boat probably would have survived just fine, but we we would have had to find a laundry in Mattituck!

Edited by - Stinkpotter on 12/05/2014 08:23:04

Voyager
Master Marine Consultant

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USA
5231 Posts

Response Posted - 12/05/2014 : 19:27:28

After stories and scenarios like these, now whenever I go out the bottom crib board is locked firmly in place, the pop top is dogged snugly down and the port side fender locker hatch is pinned with a clevis and cotter pin.
I know none of these moves is a guarantee, but I've been caught in too many extreme conditions to not keep my guard up.
As we all know Sailing has been defined as "hours of boredom punctuated by moments of terror!" I might not agree with the boredom part, but we've all had our moments, haven't we?

Edited by - on

Akenumber
Navigator

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USA
247 Posts

Response Posted - 12/06/2014 : 10:49:29

Just curious what technique you use to lock down your bottom crib board.

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sweetcraft
Admiral

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USA
816 Posts

Response Posted - 12/06/2014 : 21:52:25

During each of our knock downs the rudder was out of the water but no water came into the cockpit. The spinaker was sheeted and was full of water but emptied as we came back up and it was also released so no damage to it. Three of the crew was forward which put weight more to the bow which maybe was why no water in the cockpit. Then with the 150 knock down my elbow was in the water but no water in the cockpit. Yes inland lake and not large waves make it just an incident.
I like the idea of keeping the lockers secure but to secure a hatch for me would take pins. I try to not get into a blow by watching the weather. When cruising in the NW I try to have an alternate course ready when the wind and waves kick up. Even with attention to weather reports coming around an island the local conditions can be very difficult. I look for the safe harbor too.

Edited by - on

Voyager
Master Marine Consultant

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USA
5231 Posts

Response Posted - 12/07/2014 : 09:04:43

Locking the bottom crib board, there are two ways I know of:
1. Using two slide bolt locks, one on either side that slide into the frame. Use brass.
2. Thin wooden (pine) wedges - that slide in behind the crib board along the slots. Wet them a little once they're in place and they will swell and won't let go.
I take the 2nd approach as needed.
Having the bottom crib board in place can be a trip hazard for guests but if you tend to heel deeply in big water in exhilarating conditions where breaking waves are likely to occur, it's a justified precaution.
Since the bridge step is so tall on the C25, it's over kill. The most important precaution is securing the dumpster hatch always.

Edited by - on

Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 12/07/2014 : 10:17:14

Preparation for heavy weather has to be done before it hits. The greatest danger is in the leading edge of the storm, because that's usually where the wind is the strongest. Sails should be either reefed or furled before it hits. Hatches should be secured before it hits. If the boat is knocked down or capsized before preparations are made, you might not be able to do those things afterward. In a severe storm, I prefer all crew who aren't essential to sailing the boat to go down below, because when they're down below, you don't have to worry about them being swept overboard.

My C&C 35 has a single hatchboard, instead of three, and it has a barrel bolt latch inside that connects the hatchboard to the sliding hatch. If the boat rolls over, the hatchboard won't fall out, and the sliding hatch won't slide open. But, if the people inside need to get out, they can open it from inside. I wouldn't be in favor of pinning the hatchboards from the outside, because people inside would be trapped there. I don't see any particular benefit in pinning one of the hatchboards in place. IMO, the companionway should be completely closed in severe weather. If only one is in place, massive amounts of water will get inside the boat in a roll over. Closing it completely will keep much of it out.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 12/07/2014 : 11:40:59

quote:
Originally posted by Voyager

...Since the bridge step is so tall on the C25, it's over kill. The most important precaution is securing the dumpster hatch always.

Not that tall... If a big enough wave gets into the cockpit foot-well, it could flow into the companionway before it gets out of the scuppers, and the transom cut-out is higher than the companionway sill, which I hesitate to call a bridge deck--that's an actual deck, ideally higher than the coamings, you have to boost yourself over to get into the companionway on a blue-water boat. The the bottom crib-board might make the opening higher than the transom cut-out, except maybe on the '89-91 models that don't have a cut-out. (The open C-250 cockpit will dump the water immediately.) In the nastiest situation we faced, we closed up the companionway completely with my wife below and me in the cockpit until the worst of the rain subsided (and wished we had a dodger).

As long as we're talking about major broaches or roll-overs, for any single-handed C-25 sailor facing those remote possibilities, I suggest making sure your swim ladder can be lowered by a person (you) in the water, in case the boat recovers without you in it. I didn't secure mine with anything--friction held it up in all but a few instances.

Edited by - Stinkpotter on 12/07/2014 11:50:50

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